Hi Adela,
Sadly, I can't comment on most of your questions because A.) I'm new to Las Vegas myself, B.) I don't have children, and C.) I'm staying in campus housing. However, I can tell you that Highlands has been great for me so far.

I got my BA at UNM, and I'm up here for my Master's. I like it a lot more than I did UNM simply because classes are smaller and your instructors actually get to know you. The campus seems pretty safe to me - I always see campus police circling around.
There's nothing I "hate" about Las Vegas or Highlands. I guess if I had to pick one thing to gripe about, it'd be the fact that there isn't really much to do up here in your free time. But since you have children, I'm pretty sure your free time is pretty much occupied.
Good luck!
PS: There usually is a waiting list for family housing, but it wouldn't hurt to apply anyway and see what happens. I believe the family housing is called "Gregg House", and you can find the application at the NMHU site.